Door latches



Oct. 7, 1958" A. E: F. JoHNsoN DOOR LATCHES 2 Sheets-Sheet 1 Filed June 28, 1956 llh.

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DOOR LATCHES A. E. F. JOHNSON Oct.- 7, 1958 Filed June` 28, 1956' me, f

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United States Patent (I)` DUUR LATCHES Axel E. F. Johnson, Cincinnati, Ohio, assignor to American Hospital Supply Corporation, Evanston, Ill., a corporation of Illinois Application .lune 28, 1956, Serial No. 594,428

l2 Claims. (Cl. 20-19) This invention relates to door latches, and more specically to latches which are particularly useful for releasably connecting a group of sliding doors.

One of the principal objects of the present invention is to provide an eifective and easily operated device for simultaneously latching or unlatching a series of three sliding doors. Another object is to provide a door latch adapted to interconnect a group of three sliding doors, the latch mechanism being carried by only one of the doors. A further object is to provide a locking device carried by a front sliding door for interconnecting that door with a pair of slidable rear doors, the interconnecting means being retractible into the front door for unlocking the three doors and being movable to project rearwardly from the front door for locking the three doors in closed positions. A still further object is to provide a device for simultaneously latching three sliding doors together, and which operates to urge the doors into proper closing relation `as the latching device is manipulated.

Other objects will appear from the specication and drawings, in which Figure l is a broken side elevation showing one embodiment of the present invention; Figure 2 is a broken side elevation illustrating structural details of the embodiment represented in Figure l; Figure 3 is a broken horizontal sectional view taken along lines 3 3 of Figure 2, and showing the locking device in extended or latching position; Figure 4 is a broken horizontal sectional view similar to Figure 3, but showing the latching or locking means in retracted position; Figure 5 is a broken vertical cross section taken along lines 5 5 of Figure 4; Figure 6 is a vertical cross sectional view taken along lines 6 6 of Figure 4; Figure 7 is a broken side elevation illustrating a second embodiment of the present invention; Figure 8 is a horizontal sectional view showing constructional details of the second embodiment, and taken along lines 8 8 of Figure 7; Figure 9 is a hon'- zontal section similar to Figure 8, but showing the latching mechanism in retracted or released position; Figure 10 is a broken side elevation showing a third embodiment of the present invention; Figure 1l is a broken horizontal sectional view taken along lines 11 11 of Figure 10; Figure l2 is a broken vertical section illustrating the third embodiment of my invention in latching or locking position, and taken along lines 12 12 of Figure ll; Figure 13 is a `broken vertical sectional view similar to Figure l2, and showing the latching means in released or open position.

In the first embodiment of my invention shown in Figure 1 6, the letter A generally designates a door casing or frame, and the letters B, C, and D represent three sliding doors of substantially uniform dimensions carried within that frame. The frame may be composed of sheet metal, lsuch as steel sheeting, and may be formed integrally with the walls of a cabinet or cart as,`for example, a cart adapted for the transportation of food, supplies or equipment in hospitals or the like.

'I'he two rear doors B and D lie along the same horig 2,854,708 ce Patented Oct. 7, 1958 zontal plane, and the center front door C extends along a second parallel plane in front of doors B and D. All three doors may be slidably mounted within the casing in any conventional manner. For instance, the doors may be movably suspended within the frame opening, or they may ride upon the lower horizontal edge of the casing. Also, tracks (not shown) may be provided along the upper and lower edges of the frame to guide horizontal movement of the doors. Since the mounting of such doors is entirely conventional, a detailed description thereof is believed unnecessary here.

As most clearly represented in Figures 3 and 4, each of the doors B, C, and D consists essentially of a rear panel 10, 11 and 12, and a front panel 13, 14 and 15, respectively. The front and rear panels of each door are formed from a sturdy sheet material such as steel, and are uniformaly spaced apart with their peripheral edges 16 and 17 turned towards each other and secured together in overlapping relation by welding or by any. other suitable means.

In the rear panel 11 of the center or front door C are a pair of horizontally aligned rectangular openings 18. As shown best in Figure 4, openings 18 are spaced apart and are disposed adjacent opposite side edges of the center door. Between the front and rear panels of that door, and directly in front of openings 18, are a pair of horizontally elongated U-shaped channel members 19. Members 19 are thus mounted within the center door so that the horizontally elongated channels defined by those members are in communication with openings 18. Figures 2 and 6 show the channel members provided with Vertical flanges 20 which may be welded or otherwise secured to the inside surface of rear panel 11. To increase the structural rigidity of center door C, it may be desirable to also weld the base portions 21 of the U-shaped lchannels to the inner surface of front panel 14.

Witlnn the center door adjacent the opposite side edges thereof and in front of openings 18, are a pair of guide member 22 (Figures 3 and 4). The guide members are provided with rearwardly and outwardly inclined Walls 23, and may be welded to channel members 19, as shown in the drawings, or, if desired, may be formed integrally with the channel members.

The interlatching means comprises a pair of elongated arms 24 slidably carried within the channels dened by the horizontally elongated channel members 19. Preferably, each of the arms is formed from a continuous strip of sturdy and somewhat ilexible material, such as steel, which has been turned backwardly upon itself. Consequently, the ends of each reversely turned strip combine to provide the inner end portion of one of the arms 24. The ends of each strip are spaced from each other the most rearwardly disposed ends 25 being turned rearwardly and then inwardly to define recesses 26 at the inner ends of the arms. At the outer end portions 27 of the arms, the strips from which the arms are formed are spaced apart, thereby providing the arms with enlarged outer ends capable of engaging the side edges of doors B and D for securing all three doors in closed position.

Concealed within the center door and interposed between the inner end portions of arms 24 is an elliptical or oval-shaped cam member 28. As shown best in Figure 2, the generally oval cam member or plate has iiattened ends 29, and is rotatably carried by a central shaft 30 which projects through the front and rear panels of the center door. A handle 31 is mounted upon the front end of shaft 39, and the rear end of that shaft which extends through panel 11` is equipped with a pin 32 and washer 33. Preferably, rear panel 11 is recessed about the opening through which sha-*ft 30 projects so that the rear end of that shaft 4does not extend beyond a horizontal plane along the rear surface of the center door.

A pair of tension springs 34 have their ends hooked through openings 35 at the inner ends of the slidable arms, and urge those arms toward each other. The arms are therefore urged into engagement with the generally curved periphery of cam member 28. As illustrated in Figures 3 and 4, peripheral portions of the cam member project into the recesses 26 provided at the inner ends of the arms, thereby insuring proper cooperation between the elongated arms and the rotatable cam plate.

It is believed evident from the foregoing description that the latching mechanism illustrated in Figures 1 through 6 is operated by rotation of handle 31. When the handle is turned so that the major axis of cam plate is vertically disposed (Figure 4), tension springs 34 will draw the elongated arms into retracted positions within the center door. The three sliding doors B, C and D are then unlatched and may be moved independently within frame A. Since the retracted arms are carried between the front and rear panels of the center door, they provide no obstruction to the free sliding movement of the doors.

When interlatching Aof the three sliding doors is desired, the doors are simply moved into the positions illustrated in Figure 1, and handle 31 is then rotated in either direction. As the handle is turned, the recessed inner ends of sliding arms 24 travel along the` curved periphery of the cam plate, with the result that the arms are driven outwardly within the center door. At the 'same time, the outer end portions 27 of the arms are cammed rearwardly by the sloping walls of members 22. Finally, when the major aXis of the cam member 28 assumes a horizontal position, as shown in Figures 2 and 3, the enlarged end portions of the interlatching arms 24 abut the side edges of doors B and D to securely latch all three doors in closedposition. Therefore, by merely rotating handle 31, all three sliding doors are securely and simultaneously interlocked.v It is believed apparent that as the sliding doors are being positioned for locking, it may be dicult to accurately space the center door C at equal distances from the side walls of the door frame. However, the interlocking means operates to correct'inaccurate positioning of the center door as handle 31 is rotated. For example, if the center door is accidentally placed too far to the left, then as the handle is rotated, the outwardly moving left arm 24 will abut door B before the other arm engages door D. Consequently, the left arm will tend to shove the entire center door to the right until the other arm also engages its respective rear door, thereby automatically centering the front or center door C.

It is to be noted that when the doors are interlocked, the recessed inner ends of arms 24 are seated against the flattened ends of the cam plate 28. As the cam plate is rotated in either direction from this position, the corners of the plate adjacent attened edges 29 tend to urge the arms 24 a short distance outwardly towards rear doors B and D. Since the outer ends of the arms are already in engagement with the rear doors, the initial rotational movement of the cam plate causes the arms 24 to flex forwardly in order to accommodate the outward force directed thereagainst. Similarly,when the latching arms are being shifted from a retracted into an extended position, they will bow slightly as the corners of the cam plate pass through recesses 26. Since the arms must hex slightly as they are shifted from or into the fully extended position shown in Figures 2 and 3, it is believed evident that when the arms have been fully extended, they will tend to remain in that condition despite vibration or movement of frame A or impact upon the frame and the sliding doors carried thereby.

Figures 7-9 show another embodiment of my invention for simultaneously interlocking the three sliding doors B', C and D'. Like the sliding doors alreadly described, doors B', C' and D' are equipped with rear panels 36, 37-and 38, and front panels 39, 40 and 41, respectively. In the rear panel 37 of the center or front door C are a pair of horizontally aligned and laterally or outwardly tapered openings 42. The edges of rear panel 37 forming the inner borders of openings 42 are preferably turned forwardly and inwardly to provide rein forced lip portions 43. As shown best in Figures 8 and 9, an inner wall 44 which may be formed integrally with rear panel 37, slopes inwardly and forwardly from the outer limits of each opening and has its inner edge welded or otherwise secured to the rear surface of the front panel 40.

The lips 43 and the inclined walls 44 serve to guide the door interlatching means, which consists essentially of a pair of elongated exible arms 45 carried by a rotatable yoke 46. The elongated yoke has an opening 47 extending therethrough intermediate its ends, and is carried upon the enlarged portion 48 of a rotatable shaft 49. As illustrated most clearly in Figure 8. one end of shaft 49 is rotatably received within a central aperture in rear panel 37, while the other end of the shaft projects through a corresponding aperture in the front panel 40. A handle 50 having a recessed shank portion 51 is tightly fixed upon the forwardly projecting end portion of'shaft 49 by a key 52 or by any other appropriate attaching means.

' The inner end portion of each locking or latching member 4S is apertured to pivotally receive a pin 53 carried by a pair of fingers 54 at each end of the yoke 46. Consequently, as the handle and yoke are rotated, the latching members or arms 4S are simultaneously shifted either inwardly or outwardly between the front and rear panels of the center door C. The outer end portions of the exible arms are preferably enlarged, and may be provided with shoulders S5 adapted to engage lips 43 for limiting the inward movement of the exible arms.

When doors B', C and D are unlatched, the arms 4S will be retracted between the front and rear panels of the center door, and will not interfere with the free sliding movement of the doors. When interlatching of these three doors is desired, the doors are simply moved into the positions illustrated in Figure 7 and handle'50 is then rotated in a counter-clockwise direction. The. rotating yoke drives the flexible arms 45 outwardly, and the sloping walls 44 of the center door cam the outer end portions of the arms rearwardly so that they are brought into abutment with edges of doors B' and D' (Figure 8). As the arms travel outwardly, lips 43 cooperate with the inclined walls 44 to eX or bow the arms, thereby insuring proper engagement between the ends of those arms `and the rear doors. As in the rst embodiment of the present invention illustrated in Figures 1-6, all three of the sliding doors are securely and simultaneously interlocked upon rotation of the handle carried by the center door.

Figures 10-13 show a third form of my invention for simultaneously interlocking the three sliding doors B", C and D. These doors are similar to the doors already described, and are equipped with rear panels 56, 57 and 58 and front panels 59, 60 and 61, respectively. Rear panel S7 of the center door is provided with a pair of vertically elongated slots or openings 62 adjacent each side edge of that door, and the front panel 60 has a vertically elongated central opening 63.

The interlocking means comprises a cylindrical, elongated bar 64 having opposite end portions 65 turned in the same direction at substantially right angles to the remainder of the bar. These end portions may be sheathed by short sections of tubing 66 composed of a resilient material such as rubber. The elongated bar 64 is rotatably carried between the front and -rear panels of the center door, and is mounted upon the forward side of rear panel 57 by means of a pair of connecting plates 67. Each of-the plates is welded orotherwise secured to the rear panel, and provides a longitudinally extending U-shaped channel adapted to rotatably receive bar 64.

As clearly shown in' Figures 10 and I1, the two plates 67 are spaced apart at the center of the door adjacent opening 63, thereby exposing a relatively small center portion of bar 64. A handle 68 having one end welded or otherwise attached to the center portion of bar 64 projects through openings 63 in front panel 60. The handle is therefore easily accessible from the front of door C, and may be lifted or lowered to rotate bar 64.

From Figures and ll, it will be seen that the sheathed end portions 66 of bar 64 are aligned with the vertically elongated slots 62 in the rear panel 57 of door C". When handle 68 isv lowered, these end portions pivot upwardly through slots 62 to' simultaneously inter* lock doors B, C" and D. Except for these rearwardly projecting portions, the rear surface of door C is smooth and unobstructed. When handle 68 is lifted (Figure 13), the end portions of b'ar 64 are withdrawn or retracted through slots 62, into' the recess between the panels of the center door, and the three sliding doors are thereby simultaneously unlocked.

While I have disclosed the foregoing embodiments of my invention in considerable detail for purposes of illustration, it will be understood by those skilled in the art that many of these details may be varied without departing from the spirit and scope of this invention.

1. In a sliding'door structure equipped with a door frame adapted to receive three slidable doors, a pair of rear doors each slidably carried by said frame and extending along a first plane, a front door slidably carried by said frame and extending along a second plane parallel to said first plane, said front door being provided with interlatching means for engaging said rear doors and for simultaneously interconnecting all of said doors, and a single handle provided by said interlatching means for operating the same.

2. The structure of claim 1 in which said interlatching means is movable between a latching position in which said means abuts the inner edges of both of said rear doors and an unlatching position in which said means is retracted into said front door.

3. The structure of claim 2 in which said interlatching means comprises a pair of horizontally extending arms slidably carried by said front door, a cam member rotatably carried by said front door, and spring means connecting said arms together and urging the inner ends of said arms into engagement with the cam surface of said member, said cam member being adapted to drive said arms outwardly upon rotation thereof, and means for guiding the outer ends of said arms rearwardly as said arms are driven outwardly upon rotation of the cam member.

4. The structure of claim 2 in which said interlatching means comprises an elongated bar rotatably mounted upon said front door and having end portions adapted to abut the inner edges of said rear doors when said bar is in latching position and to retract into said front d-oor when said bar is in unlatching position.

5. The structure of claim 2 in which said interlatching means comprises a pair of ilexible arms, said arms having the inner ends thereof pivotally secured to a yoke rotatably carried by said front door and being adapted to move outwardly as said yoke is rotated, said front door also being provided with cam means for directing the outer ends of said arms rearwardly when said arms are moved outwardly upon rotation of said yoke.

6. In a sliding door structure providing a frame adapted to carry sliding doors, a pair of slidable rear doors extending along a iirst plane and a single front door extending along a second parallel plane, said `doors each having spaced apart front and rear panels, and latching means movably mounted upon said front door and 6 adapted to move between a latching position wherein said means engages both of said rear doors and a retracted position wherein said means is retracted between the front and rear panels' or' said front door.

7. The structure of claim 6 in which said latch means comprises aA pair of elongated exible arms, a yoke rotatably carried by said front door between the front and rear panels thereof, said arms each having one end pivotally mounted upon said yoke, said rear panel of said front door being provided with a pair of horizontally aligned openings, said front door also being pro vided with a pair of outwardly and rearwardly sloping inner walls extending between the front and rear panels thereof and adjacent said openings, whereby upon rotation of said yoke said arms are simultaneously moved outwardly and exed rearwardly to project through said openings and engage said rear doors.

8. The structure of claim 6 in which said latching means comprises a horizontally elongated bar rotatably carried by said front door between the front and rear panels thereof and having integrally formed right-angled end portions, said rear panel being provided with a pair of openings adjacent the end portions of said bar, and handle means for rotating said bar and for moving said end portions between latching and retracted positions.

9. The structure of claim 6 in which said latching means comprises a pair of elongated horizontally extending arms slidably carried by said front door between the front and rear panels thereof, an oval-shaped cam member rotatably mounted within said front door between the front and rear panels thereof, and tension spring means for urging the inner Opposing ends of said elongated arms into engagement with the oval periphery of the cam member, said rear panel of said front door being provided with a pair of horizontally aligned openings adjacent the outer ends of said elongated arms, said front door also being provided with a pair of outwardly and rearwardly sloping inner walls adjacent said openings and between the front and rear panels thereof, whereby, upon rotation of said cam member, said arms are cammed in opposite directions by said member and the outer ends of said arms are guided through said openings by said rearwardly sloping inner walls.

l0. In a sliding door structure having a frame for carrying a plurality of sliding doors, a pair of slidable rear doors extending along a first plane and a single front door extending along a second parallel plane, said doors each having spaced apart front and rear panels, a shaft rotatably carried by said front door and lying along a plane normal to the front and rear panels thereof, a cam member having an elliptical periphery and being centrally mounted upon said shaft between the front and rear panels of said front door, said front door having a pair of spaced apart and horizontally aligned openings in the rear panel thereof, a pair of movable elongated and horizontally aligned arms normally carried within said front door between the front and rear panels thereof, said arms having outer end portions adapted to extend through said openings and having inner end portions engaging the elliptical periphery of said cam member, said front door also being provided with outwardly and rearwardly sloping inner walls adjacent said openings and between the front and rear panels thereof, and handle means carried by said shaft for rotating said cam member, whereby, upon rotation of said cam said arms are urged in opposite directions and the outer end portions thereof are directed through said openings by said sloping inner walls for simultaneously latching and unlatching all of said doors.

1l. In a sliding door structure having a frame for carrying a plurality of sliding doors, a pair of slidable rear doors extending along a rst plane and a single front door extending along a second parallel plane, said doors each having spaced apart front and rear panels, a shaft rotatably carried by said front door and lying along a plane perpendicular to the panels of said` door, an elongated yoke mounted intermediate itsends upon said shaft and between said front and rear panels, a pair of elongated exible arms having inner ends pivotally mounted upon opposite ends of said yoke, said rear panel of said front door having a pair of spaced apart and horizontally aligned openings, handle means for rotating said yoke and for moving said flexible arms outwardly and in opposite directions between said panels, and cam means for directing the outer ends of said arms rearwardly through said openings as said arms are driven outwardly, whereby the outer ends of said arms are adapted to engage said rear doors for centering said front door and for simultaneously interlatching all three doors.

12. In a sliding door structure equipped with a door frame adapted to receive three sliding doors, a pair of rear doors each slidably carried by said frame and eX- tending along a rst plane, a front door slidably carried by said frame and extending along a second plane parallel to said first plane, said front door being provided with interlatching means for engaging said rear doors and for simultaneously interconnecting all of said doors, said interlatching means including a pair of laterally movable arms carried by said front door and simultaneously engageable with the opposing vertical edges of said rear doors, whereby, when said front door is disposed between said rear doors and said rear doors are spaced apart, said rear doors are moved laterally in opposite directions and said front door is interlatched therewith as said arms are moved laterally.

References Cited in the file of this patent UNITED STATES PATENTS 

